1. Field of the Invention
The present invention relates in general to internal combustion engines and more particularly to the internal combustion engines of a fuel direct injection spark ignition type that adapts a system for injecting fuel directly into the combustion chamber and igniting the air/fuel mixture in the chamber using a spark produced by a spark plug. More specifically, the present invention is concerned in an arrangement of intake ports formed in a cylinder head of such engines.
2. Description of the Prior Art
In providing a cylinder head of an internal combustion engine with two intake ports for each combustion chamber, it has been commonly employed that, due to the inherent separation from a single intake passage, the two intake ports are arranged to extend in parallel or extend while increasing a distance therebetween as nearing the combustion chamber.
Particularly, in the internal combustion engines of the above-mentioned type, it has been commonly employed that a fuel injector is arranged below and between the two intake ports, that is, at a peripheral side of the combustion chamber. This arrangement is shown in for example Japanese Patent First Provisional Publication 9-119344.
In this Publication, there is also disclosed a cooling water passage formed in the cylinder head near a lower portion of a fuel injector mounting bore. With this, a fuel injector installed in the mounting bore and fuel fed to the fuel injector are cooled during operation of the engine.
Beside, in Japanese Patent First Provisional Publication 6-101588, there is disclosed a system for suppressing over-heating of fuel injected by the fuel injector. That is, in the system, a return part of the fuel from the fuel injector is controlled in accordance with the temperature of the fuel fed to the fuel injector.